Packings for rotary engines



July 6, 1965 L. PERAS PACKINGS FOR ROTARY ENGINES 4 Sheets-Sheet 1 Filed Aug. 24. 1961 July 6, 1965 L. PERAS PACKINGS FOR ROTARY ENGINE 1S Filed Aug. 24, 1961 4 Sheets-Sheet 2 July 6, 1965 L. PERAS PACKINGS FO R ROTARY ENGINES 4 Sheets-Sheet 3 Filed Aug. 24. 1961 HQ 7 171 Va 7 77- A/ A) uc/en eras 7753.? 2

Fig. 8

L. PERAS PACKINGS FOR ROTARY ENGINES 4 Sheets-Sheet 4 July 6, 1965 Filed Aug. 24. 1 961 Inrenfor uu'ep ercs 7m ,Vb/A'A,

mw w,

14/77;- pay;

United States Patent 3,193,186 PACKINGS FOR ROTARY ENGINES Lucien Pras, Billancourt, France, assignor to Regie Nationale des Usines Renault, Billancourt, France Filed Aug. 24, 1961, Ser. No. 133,631 Claims priority, application France, Sept. 17, 1960, 838,869, Patent 1,274,666 8 Claims. (Cl. 230-145) This invention relates to rotary engines of the lobar type comprising a rotor having an epicyclic contour with 2N lobes and a stator =with 2N +1 lobes, and more particularly to scaling or packing means therefor.

It is known that in engines of this general character the number of points of cont-act between the two contours of the rotor and stator equals the number of lobes of the envelope curve, that is, of the stator, and it is this number (2N+ 1) that determines the number of working chambers in which the engine cycle takes place. Associated with these (2N +1) working chambers are (2N+l) combustion chambers in which the inlet and exhaust valves and the spark plugs are mounted.

According to a particularly advantageous arrangement described in a prior patent application No. 115,657, tiled on June 8, 1961, now Patent No. 3,148,667, for Rotary Engine, the combustion chambers are formed in the lateral walls of the stator.

In this prior patent application, the rotary engine comprises a rotor having a contour corresponding to a shortened cpicycloid with two arcs, and a stator comprising three lobes separated by sealing strips constantly engaging the stator contour. Associated with each one of the three peripheral working chambers of the variable-volume type, which are formed by construction between the rotor and the stator, are constant-volume combustion chambers formed in the lateral walls of the stator, these auxiliary ridge-shaped chambers receiving the inlet and exhaust valves having their axes inclined to the engine axis as well as the spark plug mounted in the vicinity of said valves.

In hitherto known engines of this character, the joints between the working chamber and the eccentric memher on which the rotor is mounted were sealed against gas and oil leakages by elements carried by the rotor proper. However, this arrangement is characterized by drawbacks notably in that these elements are subjected to the detrimental influence of inertia and/or centrifugal force.

According to the present invention not only the aforesaid sealing or packing elements usually provided between two successive working chambers but also those intended for isolating said chambers from the central eccentric are mounted in the stator, whereby these members remain stationary during the operation of the engine.

These and other features and advantages of the invention will appear more clearly as the following description proceeds with reference to the accompanying drawings illustrating typical embodiments of the invention. In the drawings:

FIGURE 1 is a diagrammatical section taken across the engine axis, the upper or front cover thereof being removed to show the rotor inside the stator;

FIGURE 2 is a view taken from the inner side of the upper or front cover to show the combustion chamber as well as the packing elements;

FIGURE 3 is a detail view showing on a larger scale the packing disposed between the working chambers;

FIGURE 4 is a fragmentary section taken upon the line IVIV of FIG. 3 to show the sealing between the stator and rotor;

FIGURE 5 is a fragmentary section taken upon the line V-V of FIG. 1;

FIGURE 6 is a view similar to FIG. 1 but showing an alternate embodiment of the packing;

FIGURES 7 and 8 are views similar to FIGS. 3 and 4 which correspond to the embodiment of FIG. 6;

FIGURE 9 is a view similar to FIG. 2 but showing another form of embodiment of the polygonal sealing device;

FIGURE 10 is a section taken upon the line XX of FIG. 9;

FIGURE 11 is a detail view showing on a larger scale the sealing device between two working chambers corresponding to the modified embodiment of FIG. 9, and

FIGURE 12 is a section taken upon the line XII-XII of FIG. 11.

According to this invention, a rotary engine of the aforesaid lobar type is sealed against gas and liquid leakages by pr-oviding fixed partioning means inserted in the stationary or non-rotating cases, that is, in the stator and in the side covers. These partitioning means are constructed according to three main types:

(1) Radial partitioning means disposed between the adjacent working chambers.

In this case, the partitioning means consist of strips or sections housed in suitable recesses formed in the stator at the junctions of adjacent lobes. These strips bear resiliently on the rotor along one generatrix.

(2) Polygonal lateral partitioning means carried by the lateral walls or covers.

They consist of straight or arcuate strips or sections inserted in grooves interconnected to form a polygon of which the sides are so designed that they are not un-cov 'ered by the rotor during its rotation, and that on the other hand these partitioning strips or sections be located as close as possible to the combustion chambers.

According to a specific form of embodiment, members for interconnecting the strips are provided with a view to avoid leakages from one chamber to another externally of the polygon, or to permit the sealing relative engagement between the radial and lateral strips.

(3) Circular lateral partitioning means disposed inside the polygonal partitioning strips which are also housed in the lateral flanges or covers and are intended more particularly to avoid oil leakages.

In the exemplary form of embodiment of a rotary engine which is illustrated in FIGS. 1 to -4 of the drawings, the reference numeral 1 designates the stator, 2 is the rotor and 3 the radial sealing strips fitted in grooves 4 formed in the stator. FIG. 2 illustrates the lateral cover 5 in which the combustion chambers 6 containing the inlet and exhaust valves 7, 8 and the spark plug 9 are disposed.

This cover as well as the opposite cover is forged with grooves 10 constituting together a polygon of which the vertices register with the strips 3, the sides of the polygon being either straight (FIG. 6) or curved ('FIG. 2), and their design such that they cannot be uncovered by the rotor while being located as close as possible to the combustion chambers.

These grooves 10 open at their vertices into cavities 11 also formed in the covers.

On the other hand, these covers are also provided with circular grooves 12 receiving the oil sealing device which may be of any suitable type.

Thus, as shown in FIGS. 3 and 4, the radial strips 3 inserted in grooves 4 are urged by corrugated leaf springs 13 for resilient engagement with the suitable rotor contour so as to prevent the gases from communicating from one working chamber 14 to an adjacent chamber.

T 0 seal the chambers against gas leakages to and rom the central portion in which the eccentric is mounted, adequate sections 15 are inserted in the grooves 10 and urged by springs 16 (FIG. 5).

The lateral fluid-tightness in the engine is obtained by i is possible to have access to the strips 3 fOYlHSPECllOn.

or replacement.

4; 1 claim: V l. Sealing device for a rotary engine of the lobar type comprising a rotor-having 2N lobes and a stator provided with a chamber having 2N +1 lobes and lateral covers closing said chamber, wherein the rotor contour 1 is an epicycloid and the stator-chamber contouran en- FIGS. 6 to 8 illustrate a modified embodimentwherein the polygonal sealing strips 21 are straight and the f -lateral sealing deviceis disposed differently. V

In this alternate embodiment, as shown notably in FIGS. 7 and 8, the strips '3 engage directly with their end faces the inner faces of the covers (FIG. 8) with theminimum operative" clearance, but they are engaged in turn by small laminae 22 resiliently pressed against the side faces of the rotor by springs 23 reacting against washers 24 housed in blind holes '25. As in the preceding casev the ends of the sealingst'rips 21 engage'the laminae 22. 7 I V Finally, according to. another modified embodiment illustrated in FIGS. 9 to 12, the polygonal grooves, in-

stead of leading into the recess receiving the strips 17 or 22, are extended outwardly and openexternally'of the.

case in order to facilitate the machining'thereof and permit the use of circular tools of relatively large diameter.

Thus, as shown, the grooves 36 intersect one another as velope curve constituting a conjugate contour of the rotor epicycloid, the rotor being eccentrically mounted within said stator for rollinginterengagement of said stator and 'rotorl'lobes to form expansible and contractible fluid worldng chambers therebe'tween, said sealing device comprising lateral. and radial partitioning meanscarried only by, the stator and by fixed elements rigid with said stator,

I said partitioning means consisting on the :one hand of radial strips'disposed. between the'working chambers and hou'sed in grooves formed at the junctions ,between ad- .means carried'by said grooves formed in said stator and. in the lateral covers of the engine is urged by spring Housed in the grooves 30 are strips 31 urged by corrugated spring' blades 35 disposed'in the bottom of the relevant grooves. These sealing strips 31 of polygonal configuration are assembled at their ends but a small 7 gap 37 is left therebetween for thermal expansion.

The intersections of these polygonalgrooves are coincident with the radial grooves 4 of the stator and the corresponding strips 3 fitted therein constantly engage the epicyclic contour 38 of rotor 2- throughout their length with a surface having an adequate contour.

FIGURE 12 illustrates the assembly of sealing strips as consistent withthe conditions of operation of the engine. 1

The reference numeral 1- designates'the stator, 2 is the 1 rotor. and 5 the lateral cover, 3 is one of the radial sealing strips housed in the stator 1 and engaging the epi-' cyclic contour 38 of the rotor. I a

Each radial strip 3 is mounted in'its groove with a moderate clearance 39' at either end. Thus, a certain leakage 49 is left between'the' adjacent working chambers.

On the other hand, the lateral strips 31' constantly engage one lateral face 41 of the rotor.

At their junction they perm t throughthe gap. 37 which adds itself to the leakage it a moderate leakage Although the present invention has been described in to, be within the purview and scope of thc invention and appended claims.

" 'conjunction with preferred embodiments, it isto be undera jac'ent stator lobes, and on the other hand of strips inserted in polygon forming grooves formed in the lateral cover of the stator chamber, the contour of said polygon forming grooves beingso designed thatthey are constantlyinside the area covered bythe rotor, and being locatedin the stator they remain'stationary during the operationofthe engine and are free of any inertiaforce or centrifugal efiect. I v

2..The device of claim 1, wherein said partitioning meanstowarcls the registering bearing face of the rotor to provide a sealing joint therewith. V

.3.-The dew'ce of claim 1, wherein said partitioning means comprises further strip-like elements disposed in circular grooves formed in the lateral covers of the v stator chamber said grooves surrounding the shaft carry ing the rotor and extending'into said covers.

4. The device of claim 1,, whereinsaid'partitioning means comprises further at the vertices of said polygon forming grooves other strip elements; pressed by spring means outward from the bottom of their. recesses'and engaged by the elements of said polygon forming partitioning means andalso by said radial strips.

5. The device of claim. 4, wherein ,said other strip; elements are, disposed end to end and constitute the extensions of said'radial strips.

6. The 1 device of claii 4; wherein said other strip elements are coincident with said radial strips but somewhat shiftedin the radial direction in relation thereto in 'orderto constitute a shoulder forlsaid strips,

7. The device of claim-4, wherein the recesses for receiving said other strip elements consist of slots formed in a detachable plug carriedby the stator.

8. The device'of claim 1, wherein said polygon forming groovesxextend to the outer edges of the covers, and

plug means, closing inoperative portions ofsaid grooves.

Examiners. 

1. SEALING DEVICE FOR A ROTARY ENGINE OF THE LOBAR TYPE COMPRISING A ROTOR HAVING 2N LOBES AND A STATOR PROVIDED WITH A CHAMBER HAVING 2N+1 LOBES AND LATERAL COVERS CLOSING SAID CHAMBERS, WHEREIN THE ROTOR CONTOUR IS AN EPICYCLOID AND THE STATOR CHAMBER CONTOUR AN ENVELOPE CURVE CONSTITUTING A CONJUGATE CONTOUR OF THE ROTOR EPICYCLOID, THE ROTOR BEING ECCENTRICALLY MOUNTED WITHIN SAID STATOR FOR ROLLING INTERENGAGEMENT OF SAID STATOR AND ROTOR LOBES TO FORM EXPANSIBLE AND CONTRACTIBLE FLUID WORKING CHAMBERS THEREBETWEEN, SAID SEALING DEVICE COMPRISING LATERAL AND RADIAL PARTITIONING MEANS CARRIED ONLY BY THE STATOR AND BY FIXED ELEMENTS RIGID WITH SAID STATOR, SAID PARTITIONING MEANS CONSISTING ON THE ONE HAND OF RADIAL STRIPS, DISPOSED BETWEEN THE WORKING CHAMBERS AND HOUSED IN GROOVES FORMED AT THE JUNCTIONS BETWEEN ADJACENT STATOR LOBES, AND ON THE OTHER HAND OF STRIPS INSERTED IN POLYGON FORMING GROOVES FORMED IN THE LATERAL COVER OF THE STATOR CHAMBER, THE CONTOUR OF SAID POLYGON FORMING GROOVES BEING SO DESIGNED THAT THEY ARE CONSTANTLY INSIDE THE AREA COVERED BY THE ROTOR, AND BEING LOCATED IN THE STATOR THEY REMAIN STATIONARY DURING THE OPERATION OF THE ENGINE AND ARE FREE OF ANY INTERIA FORCE OR CENTRIFUGAL EFFECT. 